In recent years, a television receiver having a display with a size of 50 inches or more, such as a liquid crystal display or a plasma display, has been developed. In such a television receiver, a user can view on a big screen a picture such as a movie or a television program, for example.
In addition, a display device, such as a projector, in which the user can adjust a size of an image displayed on a display surface has prevailed widely. For example, in Patent Literature 1, disclosed is a technology to increase a size of a small screen displayed on a display device as a user goes away from the display device. In addition, in Patent Literature 2, disclosed is a technology to change a size with which a character or a figure is displayed in accordance with a distance between a grip module which a user has in the hand and a light-emitting module fixed to a television apparatus.